Method of recovering well fluids



Oct. 17, 1939.

J. P. WALKER4 ET A1.

METHOD `OF RECOVERING WELL FLUIDS Original Filed Jan. 2, 1937 2 Sheets-Sheet 1 OCt- 17, 1939- J.'P WALKER Er AL METHD 0F IRECOVERING WELL FLUIDS Original Filed Jan. 2, 1937 2 Sheets-Sheet 2 JW Mame w/A/ I( fbmm/ Reissued Oct. 17, 1939A UNITED STATES PATENT OFFICE 21,239 e ME'rnon oFnEcovEmNc WELL ELUms Ware Original No. 2,080,351, dated'May 11, 1937, Serial No. 118,890, January reissue November 14,

18 Claims.

This invention relates to new and useful improvements in methods of recovering well fluids.

. The invention has to do with the recovery of certain hydrocarbon fluids, usually produced or accumulated from the well stream or well fluids in a more or less vaporous form, which when converted into a liquid phase, will have lthe characteristics of the native liquids normally present in the well uids; and also whereby the residual g'as may be utilized or disposed of in any suitable manner, or recovered at such pressures as to make for economical and eflicient delivery to input wells for preserving reservoir pressure and minimizing precipitation within the reservoir, and for displacing and replacing reservoir products, as well as for processing at a minimum cost of equipment, maintenance and operation.

In recent years wells have been drilled to deeper depths and the physical aspects of the 20 gaseous products vin the formations show a considerable change in character from the gaseous products normally in the more shallow pools. Among the most prominent of these changed characteristics of the deeper pools is the presence of some of `the petroleum fractions, generally. called distillates", in a Vaporous form and in increasing amounts as compared to the 'shallower pools, probably due to the higher subsurface temperatures and pressures prevailing in the deeper formations. When these fractions or products are converted or changed into a liquid phase, they may be approximately water-white in color, or in some instances may be more or less colored, and are generally known in the oil fields as distillates.

Since the fixed gases in these relatively deeper pools, and vaporous products, are both in a common phase under sub-surface reservoir conditions, they are, therefore, not separable while in place in the reservoir under ordinary or controllable conditions. Consequently, when it becomes desirable to produce either the xed gajses or the vaporous products, it is ,substantially impossible to produce one without the other from the said common reservoir.

For economic reasons, certain of the products are in demand and may be readily marketed when recovered, and such products are usually those which can be converted by condensation, liquefaction, absorption, or other means, into a liquid phase. From this it follows that there may remain products which, for economical reasons, are not marketable or are not in current demand, and such products usually take the form of residual gas. To avoid the wasteful release of 2, 1937. Application for 1938, Serial No. 240,378

(Cl. (i2-175.5)

such gas, or other products, into the air or other:-

wise, sit has been found feasible and practical,

under certain conditions, to return the residual gas to a sub-surface reservoir, or to the source from which it was produced.

In the ordinary process or method of producing the vaporous products from the reservoir or bottom of the well, a certain amount of condensation from the vaporous form to the liquid phase usually occurs during the passage or transit of the gaseous fluids up the Well from the bottom to the top, whether the means of conducting the uids be through the casing oi the well, or through'the tubing, or both. Such condensation results primarily from the temperature change or dropwhich naturally takes place during the passage of the uids from the high temperature horizon or zone at the base of the well through the progressively lower temperature horizons or zones upwardly toward the surface of the well. The condensation also is brought about by heat exchange, due to the flow of the warm vaporous products through the cooler casing and earth horizons encountered as the passage continues upward in the well.

When these products arrive at the surface they are, therefore, produced at a temperature usually considerably lower than their temperature at the base of the Well bore. However, under `common practice, the amount or quantity of liquids which is condensed during this passage is only a portion of those liquelable fractions which could be condensed, were the process of heat exchanging and cooling tocontinue in the same manner or proportion. Due to the limitation of the natural heat exchange which, as above stated, takes place between the bottom of the1 well and the surface of the well, it becomes desirable to mechanically continue the process of heat exchanging at the surface, or to employ some other method to fully recover the liqueable fractions from use this method to recover such hydrocarbons.

In the methods or systems now in common use,

it is the practice to use mineral seal or some other foreign ollas an absorbing medium, there- "fore before the recovered liquids can' .be used or sold, they must be treated to remove the mineral seal oil or other absorbent. Such a step requires heating or' distilling and costly equipment' and high operating costs are involved in extracting such an absorbent.' So .far as the recovery 0f liquids. is concerned, it is not ecol nomically practical to use methods of the mineral seal type under usual conditions, at high pressur'es, and particularlyv where the residual gas is returned to the sub-surface reservoir.,

The process or method of recovering the nonrecovered fractions present in vaporous form or liquid phase, and remaining in the well fluids- 'after the natural condensing of the liqueilable fractions by the transit of well fluids upwardly. in the well, may be accomplished by using certain of a number of hydrocarbons as a densifying and liquefaction liquid. However, either the native liquid recovered 4from the well stream, or an equivalent having 4kindred characteristics, is used fluids or the well stream, or the gaseous iluidsof the well streams, at a desired point either in the upper end of the well, or on the surface, at some suitable stage in the method or system which may be in advance oi a separating step, or between separating steps, or before final segregation of the liquids and gases. Tl'ie adnuxture or introduction of these natural or native orother suitable liquids into the well fluids or Well stream, in any of the ways set forth, serves to increase the liquid content of the fluids being treated to promote recovering therefrom additional native liquids.

A further object ofthe invention is to provide an improved method, wherein the liquid and liqueflablecomponents of distillate range in the well stream or well uids are brought into more intimate contact and the liquid content of such stream is increased, by the introduction of a native liquefaction liquid having substantially the same components as the liquid and liqueilable distillate fractions o f said stream. By the introduction Aof such a. liquefaction liquid in sumcient quantities and the consequent increase of the liquid content of the ilowing stream, the liquid .surface exposed for contact with the liquid and liqueiiable fractions of the well stream is such scribed wherein the recovery of liqueable fracor admixedafter a separating step or betweenf separating steps: which variations of the method tions of distillate range from well fluidsm'ay be carried out by. admixing with suchiluids aV liquefactionY liquid ofthe character described in advance or prior to a separating step; also a method whereby the liquefaction liquid may 'be'introduced liquids.

having the advantage of increasing the recovery of ascertained liquids in a practical and profitable manner and in increasing amounts Without con` taminating the well i'luids beingtreated with foreign substances during the recovery steps, andl also producing a residual gas capable of economic processing and requiring only minimum compression for introduction into a sub-surface reservoir.

-Ak particular object of the invention is to provide an improved 'method for recovering well liquids of thecharacter described which includes admixingwith the well stream or well uids, l

.quantities .of the nativeor natural'liquid of disl tillate range and in excess of the normal distillate contentof the well stream, whereby contamination of the recovered liquids with either a foreign liquid or a blending liquid or some other substance which either changes the recovered liquid from its natural components in the well or makes additional separation or distillation necessary, is prevented.- So long as the liquefaction liquid has the characteristics herein set forth it 'may bel acquired from any suitable source, but it is preferable and probably more economical to provide the same by utilizing quantities of the recovered In this latter event, it is desirable to accumulate the yrecovered liquid in such volume as to provide ample quantities for recycling the same as the liquefaction liquid. These also, are objects. of the invention, as well as the selective con'- trolling and regulating o f the supply of liquefaction liquid over a wide range.

Another object of the invention is to provide an improved method whereby the uids may be produced under well pressures, and the method performed without altering or reducing the well-head pressure, thus making it possible to carry out the steps at relatively high pressures for the purpose of saving gas, as well asffor economic compression provide an improved method involving the in troduction into or the admixture with the well stream or well iiuids of a cool liquefaction liquid of the character described, whereby the liquid content of the well stream is increased and the temperature thereof is reduced at a single step, thus making for increased liqueiaction of the entrained liqueable fractions in vaporous form, and utilizing heat exchange, aswell as relatively high pressures; permitting 4control of. the gas-toliquid ratio and reducing atomization; and also ailording highly profitable Aliquid recovery without resorting to sub-normal temperatures, the result being accomplished either by the inherent tem'- perature of the liquefaction liquid or by first cooling said liquid. v

A very important object of the invention isto provide an improved vmethod utilizing a liquefaction liquid of the character described which .may be pre-cooled, as hereinbefore set forth, or

which owing to the inherent temperature of the well'streamor well fluids need not be cooled; or

wherein the well stream fluids may be cooled prior to theintroduction of the liquefaction liquid; or wherein the well fluids and liquefaction liquid maybe cooled after admixture, any of such procedures producing the desired liquefaction of the liqueable fractions and the advantageous results herein set forth.

A vfurther object oi-the invention is to provide an improved method for recovering well uids wherein the composition -oi the products re- -coveredv are controlled by varying the rate 'ofIA stmsnother object or the invention is to pro- 4vide a method wherein thewell stream' ilowing from the well is admixed with a liquefaction liquid of the character described and carried vthrough a stage wherein the travel of the well nulas land theiiquefacuon liquid is sumcienuy yatnpliiied to eiiect an adequate admixture and consequent recovery of the desired distillates.

It is one of the objects of the invention to gg -provide an improved method for recovering from well fluidsfiowing under pressure, certain liquid fractions, -which are predominately in vapor phase form, as well as the residue gas; in an economical and-efficient manner, whereby waste g5 -or gaseous uids and liquids is prevented, costs are reduced and conservation of' natural re-A sources may be carried out.- Y

Another object of the inventionl is to provide an improved lmethod whereby the uids which y are produced from a well underpressure, and particularlyA those which: are under relatively high pressure, may be ,separated with a minimum reduction in pressure loss, thus permitting said gas to be lcompressed to raise its pressure at a g5, very low cost.

This application is filed asa continuation in part of our cci-pending application led May 26, 1936, Serial No. 81,968.

A construction designed to carry out the in- 0 vention will be hereinafter described, together with otherfeatures of the invention.

'I'he invention will be more readily understood .from a reading of the following specincation and by reference to the. accompanying drawings, in which an example-of the invention is shown, and wherein:A

Figure 1 is a diagrammatical view of an apparatus for carrying out the improved method, in accordance with the invention, and

Figure 2 is a diagrammatical view of another apparatus for carrying out the improved metho in accordance with the invention. f

The equipment set forth in Figure 1 is shown as an illustration of the application of the method to 'a distillate type of well.

In Figure 1 of the drawings, the letter A designates a well ilowingunder pressure. It is preferable to employ the method where the wellhead pressure is comparatively high, and of course, re- 60. quires a Iflowing well or its equivalent.

The well stream 4is conducted through a pipe B from the well usually without a reduction in pressure, except for the reduction which takes `place because of the now. Where the wellhead I pressure is very high, it may be desirable to reduce said pressure by a suitable means, as by valve B'. The well iluids owing through the pipe B, while having a comparatively high pressure, will usually be largely in vaporous form,

although including liquid phases. Such iluids will generally have a low oil-to-gas ratio.

As setout .in the foregoing pages, the character of these distillate wells, to which the method is applicable, is somewhat diieent than the ordlf' `.m nary oil gas well, "because the hydrocarbon liquid phase content of the well stream is not only low but the liquenable fractions which are sought to be recovered are predominately in vaporous form and not subject toemcient recovery or separation by ordinary methods now in 5.;- common use. These wells also usually ilow under considerable pressure.

As before recited, it is highly desirable to maintain the flowing pressure within certain limits and permit as little pressure drop as is feasible in carrying out the method. This method involves the recovery of liquetlable fractions by increasing the liquid content of the well fluids through the introduction, o`r admixture therewith, o'f a liquefaction liquid, either with orf15 without temperature variations. This method may also involve the control of the temperature of the well stream or well fluids together with the admixture of native or equivalent liquids with the well uids for the purpose of increasing the liquid content of said iluids, thus accomplishing increased surficial contact and liquefaction of the liqueiiable fractions for the subsequent separation of the liquids from the gases. The operation of this -method at high pressures is advantageous since the degree of atomization or dispersion of liquid particles, prevailing under these conditions, is reduced to considerably less than would be the case if the admixture and subseq'uent separation were carried out at relatively low pressures.

Auids, at the point of introductiomit is not necessary to resort to extremelylow or sub-normal temperatures for eiiicient liquid recovery. Not only is a reduction in the temperature of the well fluids secured by the heat exchange resulting from the contact of the components themselves, when the cool liquefaction liquid is introduced, but such introduction or admixture increases the liquid mass of the well fluids.

Many types of devices may be employed for introducing or injecting the liquefaction liquid into the well uids or for admixing the same while under pressure. A container or tank C, has proven very satisfactory. The pipe B enters the tank at one side near the bottom. 'I'he interiorof the tank may varyaccording tothe conditions of operation and there may be baflies C' or any other suitable equipment for enhancing the vmixing or heat nexchanging, or both, by amplifying or prolonging the travel path of the? admixed iiuids.

creased expense.

' The,character of the recovered liquid products may be controlled to a. great extent by regulation of the temperature within the tank C, or bythe quantity of the liquefaction medium introduced thereinto. A hand valve D is connected in the pipe D for controlling thel supply ofqthe liqueiaction liquid. This pipe nds to the coil E of a cooler or heat exchangerv P of suitable conu',

struction. The coil is connected with the force pump G, whereby the liquid is delivered to the tank at a pressure'suitable to insure its entrance into the samefor circulation therethrough.

A supply pipe H extends from a high pressure separator J to the pump and is connected with a supply pipe I. The pim H includes a valve H' between the separator and the pipe I, while the pipe I includes a valve I'. If native liquid is used the valve I' is closed, the valve H' opened, and

said liquid is supplied from the separator; whereas vif extraneous liquid is used, the valve H' is closed, the valve I' is opened, and the liquid is supplied from a suitable source through the pipe I.

If desired, the valve D' may be closed andthe liquefaction liquid or recirculation liquid may be introduced into the pipe B in advance of the tank C through a pipe N, which includes a valve N. If this latter step is followed, the admixing of the liquefaction liquid in the Well stream will bring about a temperature change inthe stream prior to entering the tank C, however, as before pointed out, it is possible to introduce the liquefaction liquid into the well stream without causing a temperature change.

A discharge pipe K leads from the top of the tank to the separator. The liquefaction medium will thoroughly admix with the well fluids while flowing upwardly therewith through the tank C. The said admixing of the liquid with the well uids will cause a liquefaction and precipitation of the liqueflable fractions which are4 in vaporous form, by its intimate or surcial contact therewith, thus making it possible to increase the recovery of the liquefable fractions from the well fluids. 'y

Ordinarily, the primary well stream of these distillate type wells is substantially composed of free gases not subject to appreciable liquefaction, fractions in vaporous form which are liqueable, and other fractions in the liquid phase. These components prevail in a state in which the liquid phase fractions are highly dispersed or atomized and form a more or less homogeneous mixture with the gases and liqueable vaporous fractions.

In the process of admixing, a major changey in the character of the well stream fluids takes place in the form of an increased liquid content which results in a unification of the highly atomized or dispersed liquid particles in the primary well stream uids with the more massive liquid `particles of` the 'liquefaction liquid. During this separation, which is eflciently accomplished due' y to the fact that the atomized or highly dispersed particles have united or combined with the more massive liquid particles of the medium. During the process of admixture any cooling of the iluids which may take place will further increase the `recovery of liquefiable fractions from the combined fluids. The fluids enriched by the liquefaction liquid flow from the tank C, under substantially high pressure, out through the pipe K. This stream flowing through the pipe K has a much greater liquid content or liquid to gas ratio than the well stream as it flows from the well and enters the high pressure separator J, preferably 'at midheight, wherein separation of the liquids from the gas takes place. The pipe K includes valves K', which may be control or regulatingv valves, or any other kind of ,valves suitable-for use in this method. Y

The well stream or fluids having been prepared for separation prior to their entrance into this separator J will yield to separation therein, the` liquids descending to the 4lower portion of the separator, and the gases rising and passing' out through the pipe L, which includes a pressure control valve L'. The recovered liquids are discharged through the outlet pipe M which includes a control valve M which may be either of the manually operated type or of the automatically operated type. Any portion of such liquids may ,be bled through the pipe H for use as a liquefaction liquid. The liquid discharged through the pipe M requires no further treatment an'd is ready for use, ordinarily as a-` commercial product.

It is pointed out that by regulating-the operation of the pump G the quantity and rate of introduction of the liquefaction liquid into either the tank C or the pipe B may be controlled. At some stages in the practice of the method, it may be desirable to employ more or less quantities of liquefaction liquid in order to procure the most eflicient recovery. of liquefable fractions. Thus the provision of an ample supply of the liquefying liquid is most desirable and, of course, such liquid It will be obvious that the lean or denuded gas discharged into the pipe L at the top of the se-p-` arator J will usually be only slightly lower in pressure than the pressure of the iiowing well fluids entering the tank C. If thegas is to be returned to al sub-surface reservoir, its pressure usually should be kept as high as possible for this purpose. It is evident that if the pressure of the well stream or fluids is considerably reduced during a recovery method, then more compression is required in order tolraise the pressure of the residual gasl for input purposes. The method herein recited involves recovery of the liquefiable fractions with minimum pressure loss throughout the system, thus making it possible to greatly reduce the cost and operation of compression equipment required for returning gas to reservoirs under high pressure.

As 'hereinbefore pointed out, our method may beused with other than wholly distillate type Wells, and some of these other types of wells may produce more or less oil, as well as' vaporous form fluids containing liqueable hydrocarbons of distillate range which are in sufficient quantities to make it profitable to recover. We have illustrated V,

in Figure 2 equipment for performing the method with these types of wells. In this fgure, the nu-V meral III designates a well owing under pressure lfrom which the well uids are conductedl by a pipe II through a choke Il. The choke is, in turn, connected with one end of a flow line pipe,

. or conductor I2. lBy means of the choke, which is adjustable, the flow of the well stream from the pipe II to the line I2 may be readily controlled.

A T I3 is connected in theline 'I2 and a valve I3 is interposed in said line between the T and choke. In case it is not desired to pass the well stream through the choke the valve I3 may be closed and said stream carried through a by-pass line |30. which has one end connected to the T I3' while itsl other end is connected in a T Ila v f pose an inlet pipe of distillates which must be separately recovered. Therefore, by introducing the well stream or well iiuids into the separator I4, the liquid low volatile hydrocarbons present in such fluids or stream as it flows from the well are separated from the gaseous uids which contain the recoverable .liqueilabl fractions of distillate range.

'I'he esidual liquids recovered in the separator I4 may be conducted to a storage tank I3 by4 an outlet pipe I1, which pipe has a control valve I3 connected therein. This valve may be loper-r ated either automatically or manually. It is to be-noted that the character of the liquids flowing from the separator may vary to a. great extent and, ofj course, will depend upon the nature of the liquids of the well stream.

'I'he liquids which are separated in the separator I4 maybe conducted to the storage tank I 3, or other disposition may be made thereof. A T I8 is connected in the pipe I1 in advance of a valve 20, which may be closed to cut oil the ilow to the tank Iii.V A pipe 2l leads from the T and includes a cutoii' valve 22. i

'By closing the valve 2|! and opening the valve 22, the liquids may be conducted to a T23, which is connected to a manifold 24,` which, in turn, is connected to stocktanks 25. Suitable control valves 24' are located in the manifold 24 adjacent each tank 25 and control the flow of liquid into the tanks. From the above, it will be evident that by manipulating the valves 20 and 22 the liquid recovered in the separator I4, may be conducted either to the storage tank Ilcr the stocl:4 tanks 25. I

In some instances, it may be desirable to utilizev the liquids separated in the Aseparator I4 as a liquefaction liquid and introduce or lniect the same into the well stream or well fluids in ad- -vance of the separator I4. For this purpose, a second outlet pipe 25 having a valve 21 connected therein leads from the lower end ofthe separator. The outerend of this pipe is connected to a yT 23 and a shortpipe 29 leads from the T tp a suitable pumq 30. 'I'he outer side of the T 23 has a pipe 3| extending therefrom and the opposite end of this pipe leads to the storage tank I3. A suitable valve!! is connectedin thekpipe 3l. With this arrangement, the pump may be .supplldwith. liquid either direct from the separator through the pipe 24 or'irom the storage tank IB, or from bothl It might be desirable to'supply the pump with an extraneous liquid and for this pur- 33 leading from a,suitable ,sourceoffsupply is connected to the pump 30. A suitable control valve 34 is connected in `said pipe. t

Thepump 3l forcesthe liquid through a pipe 33 which. has a pressure gauge therein, whereby the pressure of the liquid being pumped may be determined. In place of the pump, any suitable means may be used for propelling the liquid and placing it under a desired pressure. The other end of the pipe 33 is connected to a. T 31 which T is'connectedin the now line` I2 between v sasso tor.

the mixer I i and valve I3, whereby the liquid is.

pumped into the ilofw in advance of the separa- The pipe 33 includes a control valve 38 located adjacent the ilow line and a pressure gauge 31'. u

A suitable heat exchanger 33 is located in the pipe 33 and is so arranged as not to interfere with a free passage of\the liquid when not in opera- From the above, it will be seen that the, well stream is conducted lto the separator I4 wherein the liquids are' separated from the gaseous uids. These separated liquids may be carried to the storage tank I6 or the stock tanks 25, or both; or they may be conducted'to the pump, either' from the separator I4 or tank I6, or both, for recycling as a liquefaction liquid. When conductedv to the pump, they are forced into the pipe 36 and introduced into the flow line I 2. When so introduced, it is of course necessary `that the liquefaction liquid be placed under sufficient ilowing pressure to'enter the flowing well fluids. The introduction of the liquefaction liquid will increase the liquid content of the well fluids, as has been explaned, whereby liqueilab'le fractions present in vaporous form in said fluids are accumulated and unitedwith the liquids entrained in said fluids. The admixed well uids and liquefaction liquid lowing through the pipe I2 pass into and through the mixer I5, which latter could also be the-tank C of Figure 1. While the mixer or tank may be, in some instances, omitted, it is desirable to use the same in order to obtain a more'intimate mixture of the-l components of Cthe gaseous fluids and liquids' owing therethrough. Under some conditions, it may be desirable or advantageous to connect a heat ex- -changer 40 in the pipe I2 between the mixer and separator I4 and use. the same in conjunction with, or independently of, the exchanger 39; however, the exchanger 43 may be omitted entirely.

When the liquefaction liquid is introduced into the line I2, as above explained, liquenable fractions are accumulated and subsequently separated in the separator from the gaseous fluids, passing oil. with the liquids. If the recycling of the liquids recovered in the separator is not desirable, then it is only necessary to close the valves 21, 32, and 33 in the pipes 26, 3|,.and 38 respectively, and open the valve I8 in the outlet pipe I1, whereby the separated liquids may be conducted to the tank I6 or stock tanks 25.

The gaseous iiuids of the well stream, which areseparated (from the liquids in theseparator I4, are conducted therefrom by a iiow line 4I which leads from the upper end'thereof. l These gaseous iluids usually contain liqueiiable fractions which are not recoverable in the separator.

iThe ow line 4I has `connected therein, in the order named, a valve 42, a T 43, a mixer 44,

which may be similar 4to the mixer I5, a T 45 and a valve 46. The other end oi' the vline 4I leads into a tank 41, which may be a separator,l accumulator or stabilizer. 'A 'pipe 43 including a valve 4l is connected'to the T 4i. whereby any The manifoldincludes suitable control valves 53 into the pipe 64.

for controlling the flow into said tanks.

I n order to `recover the liqueable fractions present in the gaseous fluids flowing 'through the line 4I it is desirable to recycle 4as a liquefaction liquid quantities of the liquids which have been recovered in the tank 41. For this purpose, a second outlet pipe 55 leads from the tank 41 to a suitable pump 56, similar to the pump 30. A suitable valve 51 is connected in the pipe 55. For supplying an extraneous liquefaction liquid of the character described in connection with Figure 1, a supply pipe 58 including a valve 59 is -connected to the pump 5E. This extraneous liquid may or may not be supplied, as desired.

The pump forces the liquefaction liquid sup f plied thereto through a pipe 69 which has.its other end connected to the T 43 in the flow line 4I in advance of the mixer 44, lwhereby the liquid is introduced into the flowing gaseous fluids. The pipe 60 has a pressurey gauge 6I, as well as a heat exchanger 62, 39 and 49, connected therein. As is the case of the exchangers 39 and 40, the exchangers 62 and 63 may or may not be used. V

The liquefaction liquid introduced into the flow line4| will admix with the gaseous' fluids flowing therethrough and the liqueflable fractions of distillate rangewill be accumulated so that upon their introduction to the tank 41, these liqueable fractions will be recovered as liquids. The gaseous fluids and the liquefaction liquid introduced thereinto will pass through the mixer 44 and will be thoroughly admixed before their entrance into the tank. If desired, a heat exchanger 63, similar to the exchangers 39, 4D, and 62 may' be connected in the line 4I between the mixer 44 and T 45.

With the above arrangemenhit Willbe seen that the `gaseous fluids which are separated from the liquids of the Well stream in the separator I4 may be admixed with a liquefaction liquid prior to their entrance into the tank 41, Iwhereby the liqueable fractions present in said fluids are recovered as liquids. The liquefaction liquid may be quantities of the liquids recovered in the tank 41, or such liquid may be extraneous, being supplied through the pipe 58.

It is pointed out that the system herein described is very flexible for by manipulating the various valves, the Well stream may be admixed with a liquefaction liquid prior to a separating step or after an initial separation of liquids and gaseous uids; or the W`ell fluids may be treated both before and after a separating step. In all cases, the liqueflable fractions normally present in vaporous form are 'economically recovered'.

The residual gas which is separated from the liquid in the tank 41 is substantially denuded of liquenable fractions and is discharged from said tank through a pipe B4 which has a valve 65, either manual or automatic, connected therein. `The gaseous fluids which are discharged from the separator I4 into are under pressure, which may vary but which usually will be comparatively lor drops maybe avoided.

50 which has a`valve 5l The outer end of the pipe 59 I is, in turn, con- 1 similar to the exchangers' v tion.

treatin-g suchgases, any

the pipe .4| or from the tank 41 high. Within certain limits and ranges, this pressure maybe maintained and controlled and, therefore, excessive and wasteful pressure losses able, particularly the gas is to be for injection into input wells, as well as for other reasons. v

The pipe 64 is connected with the inlet manifold 66 of a compressor unit 61.. The discharge manifold 68 of the unit connects with a pipe 69 which, in turn, is connected with one or more branch pipes 1U leading to input wells 1I. out that the pipes 1|l are broken to indicate that the input wells are preferably. remote. A service pipe 12 including a valve 13 also extends from the pipe- 69 for conducting the compressed'gas therefrom for other purposes. When the gas is not to be compressed, a T gas discharge line B4 and a pipe 15 including a valve 16 leads from said T. By conducting the gas from the pipe 15, said gas may be returned to a sub-surface reservoir having a less pressure than the pressure of the reservoir-of the well Il). In such case, compression is not necessary.

It is to bev notedl that under some conditions the best results may be obtained in this method Where the quantity of liquefaction liquid introduced is greater, or many times as great, as the recoverable liquid content ing from the well at the point of introduction; however, the method is not to be limited either .to the amount or proportion of the liqueable liqfor economic reasons, where uid introduced or its rate or. point of introduction.

As used herein, the terms Well fluids" and "well stream mean the fluids produced by the Well, irrespective of their treatment or disposi- The term fluids is generic and refers to liquids, vapors, gaseous fluids and so-called gases.

The term vaporous form as used'herein, is intended to cover all fluids havingthe form of vapors, mists orgaseus fluids. The term recovered liquids, liquids recovered, liquid reco-very, or "separated liquids, may be applied to the liquids which are normally present in the Well stream either in liqueflable form or in liquid form and which are accumulated, recovered or sep. arated at some' stage in the method; and may also include the liquefaction liquid which is added.

By the term liquid content, is meant either or both liquid and liqueflable fractions present in the well stream. 'Ihe term liquids of distillate range covers both liquids andv liqueflable fractions which are classed as distillates and as distinguished from heavy hydrocarbons.

It is pointed out that -the invention deals with the recovery of .certain products of lhydrocarbons classified as distillates and flowing from the well in vapor form or as liqueablefractions. It is the purpose to precipitate these fractions and recover'them as native liquids without adulterating them. 'I'he invention seeks to avoid admixing with the native Well gases or liquids, when blending liquid, foreign compressed to raise its pressurelIt is, pointed 14 is connected in the of the well fluids fiow.

This is highly desirliquid or heavier hydrocarbon. The liquefaction liquid should not contain any components which are not within the range of the liquids to be extracted from the gaseous fluid. Therefore, it is preferable, but not necessary, to accumulate the recovered native liquid and recycle it as the lique-V faction liquid. It is also true that there may be produced with the gaseous fluids, quantities of water vapors, which may condense during the operation ofthe method and this water may be drawn oil'. Possibly some of thisnaturally pres ent water may still remain in the liquefaction liquid when recycled, but it is to be understood that the presence of such water is not necessary to the performanceof the method.

The terms "distillate or distillates.or of distillate range, as applied in this application,

l refer to the recoveram products of high A. P. I.

gravity range, produced from the so-called "distillate wells and from oil wells which produce a separable liquid and a gaseous fluid, from which the separable liquid maybe primarily extracted by'conventional oil and gas separation, and the "distillate or high A. P. I. gravity liquids are later recovered from the gaseousfiuid which. has been separated from the crude oil and are of such components that they come within the scope oi the so-called distillate or distillates or of distillate range as applied in our 'method. However,no present nomenclature has been found on the terms above applied except the general i andcommon oil country terminologies above recited when referred to such wells, and in some cases these same wells are commonly called water white wells, or Lwater white distillate wells, and these same wells and products are often re. ferred to as such in trade and other publications for the oil industry. Through one of the inconsistencies of nature and contrary to common knowledge, the hydrocarbons herein called distillates occur in vaporous or gaseous form under pressures within the range of retrograde condensation, whereas at pressures below the range of retrograde condensation manyof these -same hydrocarbons occur in the liquid phase. The well stream flowing from these wells while including numerous hydrocarbons is predominately gaseous and its predomlnating component is usually methane, which may run as high as ninety '(90%) per cent or even higher.- 'I'he retrograde range beginsto affect condensation so far as is now known, at somewhere between 600 and 1500 pounds pressure and may extend beyond'several thousand pounds pressure. 'I'he reservoir temperatures seem `to range from approximately 100 degrees F. upward, recoveries having been made from a reservoir at a depth of 4800 feet having a temperature of approximately `150 degrees F. These figures are merely explanatory and are so used. The invention is notto be construed as intended to include the recovery of all and every hydrocarbon of the Well stream, but as directed to the recovery of certain well products of the socalled distillate range.

What we claim and desire to secure by Letters Patent is: t 1. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a -well flowing under high' pressure, admixing with the gaseous fluids of the well stream at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as the naturali distillate liquids to b recovered from the gaseyus well stream and in such quantities as to produce in the admxture aftotal liquid content in excess of the normal amount of .such natural components contained in said well stream, said liquefaction liquid beingintr'oduced in the form of relatively large particles so` as to minimize atomization thereof and the formation offmist, concurrently ilowing the admixed v.iluids while` subjected to amplified surcial contact whereby natural distillate liquid particles oi' such size andl weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefactiwon liquid, and separating the gas from said liquid r particles to recover the natural liquids.

2, The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a well flowing under `high pressure, 'admixing with the gaseous iiuids. of the well stream at atemperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid havingsubstantially the same composition as the naturaldistillate liquids to be recovered from the gaseous well stream and in such quantities as to\ produce inthe admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization v thereof and the formation of mist, concurrently i tillate liquid particles of such size and weight as to induce precipitation and increased liquid .recovery are agglomerated with the liquefaction liquid, separating the. gas from said liquid partlcles to recover the natural liquids, and recycling portions of the recovered distillate liquids and utilizing said recycled liquids as the liquefaction liquid.

3. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate prod# ucts from a well flowing under high pressure, conducting the'weli stream through a separating stage to remove extraneous hydrocarbons and liquid products, ilowing the residual well stream containing the natural distillate well products to be recovered from the separating, stage under' high pressure,` admixing with the gaseous uids of the well stream at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition' as the natural distillate liquidato be' recovered from` the gaseous well stream `and in such quantities as to produce in the admixture a total liquid content in excess oi.' the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereofand the formation of mist, concurrently f mixing with the gaseaus fluids of the well stream at a temperature not in excess of the naturai maximum temperature of the weil stream, a. liq` uefaction liquid having substantially the same composition as the natural distillate liquids to be recovered from the gaseous well stream and u in such -quantities as to produce in the admixture a total liquid content in excess of the normal amountof suchA natural components contained in said well stream, said liquefaction liquid being introduced in the' formV of relatively large particles so as to minimize atomization thereof and the formati'on of mist, concurrently ilowing the admixed fiuidswhile subjected to amplified lrelatively lowtemperature and the recovery or liqueflable fractions is increased.

5. rI 'he method of recovering natural distillate products from wells producing such products in amount gaseous form which includes, conducting the well stream containing said natural distillate. products from a well iipwing under high pressure, admixing with the gaseous fluids of the 'well stream prior to separation of the liquids from the gases of said stream and'at a temperature not in excess of the naturall maximum temperature oi' i the well stream, a liqueractionliquid having substantlallyy the same composition as the natural distillate liquids to be recovered from thegaseous well streamand in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively largeparticles so as to minimize atomization thereof and the formation of mist, con- Ycurrently flowing the admixed iiuids while sub- Ajected to amplified suriicial contact whereby natural' distillate liquid particles of such size and weight as tov induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, and separating the gas from said liquid particles to recover the natural liquids.

6. The method of recovering` natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a well owing under high pressure, admixing with the gaseous uids of the well stream at a temperature not in excess `of the natural maximum teinl'znerature` of the wellstream, a liquefaction liquid having substantially the same com- :positionI as the natural distillate liquids to 4be recovered from the gaseous well stream and in such quantities as to produce in the admixture a total liquid content in excess o1' the normal of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently flowing the admixed fluids 'through a, prolonged travel path and under constant turbulence while subjected to amplified surficial. contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, and separating the gas from said liquid particles to recover the natural liquids.

'7. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well range.

'stream containing said natural distillate products from a well flowing under high pressure; admixing with the gaseous fluids of the well stream, at a temperatur-e not inv excessof ythe natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as thenatural distillate lliquids to be recovered from the gaseous well stream and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being -introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist,

concurrently flowing thev admixed fluids while subjected `to amplied surficial contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, separating the gas from said liquid particles to recover the natural liquids, and recycling portions of the recovered distillate liquids as the liquefaction liquid and varying the rate of introduction of said liquefaction liquid to control the recovery ofthe products.

8. The method of recovering nativehydrocarbon products occurring in gaseous form in-the reservoir at pressures within the range of retrograde condensation which includes, ilowingvthe well stream containing said native hydrocarbon products from the well at a pressure within the range of retrograde condensation, admixing with thelwell stream a liquefaction fluid including hydrocarbon components of substantially the same 'composition as some of the native hydrocarbon components tov be recovered from the well stream and in such quantities as to induce precipitation and increased recovery of the liquefiable fractions of the Well stream While maintaining said stream under high pressure, flowing the admixed :fluids while subjected to surcial contact under high pressure, whereby the native liqueable fractions are precipitated and agglomerated with the liquefaction fluid and the native liquids of the I well stream, and separating the gas from the agglomerated liquids at ahigh pressure.

9. I'he method of recovering native hydrocarl bon products occurring in gaseous form at pressures within the range of retrograde condensation which includes,'flowing the well stream containing said native hydrocarbon products from the well at a pressure within the range of retrograde, condensation, adm'ixing with the well stream Aa liquefaction fluid including hydrocarbon components of substantially the same composition as some of the native `hydrocarbon components to be recovered from the well stream and in such quantities as to induce precipitation and increased recovery of the liqueflable fractions of the well *stream and while-maintaining said stream under high pressure, ilowing the admixed fluids while subjected to surcial contact under high pressure, whereby the native liqueable fractions are precipitated and agglomerated with the liquefaction uid and the native liquids of the well stream, separating the gas from the agglomerated liquids at a high pressure, and recycling portion-s loi the recovered hydrocarbon liquids as the liquefaction iiuid under high pressure within said retrograde' condensation l0. The method Aof recovering native hydrocarbon products occurring incgaseous-form at pres- `tion which includes, flowing the well stream constream under high pressure, flowing the admixed uids while subjected to surilcial contact under high pressure, whereby the native liqueiiable fractions are precipitated and agglomerated. with the liquefaction iiuid and the native liquids of the well stream under high pressure, separating the gas from the agglomerated liquids under high pressure, recycling portions of the recovered hy* drocarbon liquids as the liquefaction fluid, and cooling the recycled liquefaction liquid prior to a mixing with lthe well stream.

11. 'I'he method of recovering native hydrocarbon products occurring in gaseous form in the reservoir at-pressures within the range of retrograde condensation which includes, flowing the well stream containing said native hydrocarbon products from the well at a pressure within the range of retrograde condensation, admixing with the well stream a liquefaction uid including hydrocarbon components of substantially the same composition as some of the native hydrocarbon components to be recovered from the well stream and ,in such quantities as to induce precipitation and increased recovery of the liquefiable fractions oiI the well stream while maintaining said stream under high pressure, flowing the admixed fluids while subjected to surcial contact under high pressure, whereby the native liquefiable fractions are precipitated and agglomerated with the liquefaction fluid and the native liquids of the well stream, and separating the gas from the agglomerated liquids under high pressure within said retrograde condensation range.

12. The method of recovering native hydrocarbon products from a well at pressures within the range of retrograde condensation which includes, flowing a well stream including said native hydrocarbon products from the well at a pressure within the range of retrograde condensation, primarily extracting. from the well stream heavier hydrocarbon liquids than those which are to be ultimately recovered, admixing with the well stream a liquefactionk fluid including hydrocarbon components of substantially the same com' position as some of the native hydrocarbon components recoverable from the well stream and inv such quantities as to induce precipitation and increased recovery of liqueiiable fractions of the well stream while maintaining said stream underA a high pressure, owing the admixed fluids concurrently while 'subjected to surficial contact under high pressure, whereby native liqueable fractions are'precipitated and agglomerated with the liquefaction iluid and the native liquids of the well stream, and separating the gas from the agglomerated liquids under high pressure within said retrograde condensation range.

13. The method of recovering native hydrocarbon products from a well at pressures within the range of retrograde condensation which includes, flowing a well stream including said native hydrocarbon products from the well at a pressure within the range of retrograde condensation, cooling the well stream, admixing with the well stream a liquefaction fluid including hydrocarbon components of substantially the` same composition as some. of the native hydrocarbon components to be recovered from the .well stream and in such quantities as to induce precipitation and increased recovery of liqueable fractions of the well stream while maintaining said stream under high pressure, ilowing the admixed uids concurrently while subjected to surilc'ial contact under high pressure, whereby native liqueflable fractions lare precipitated and agglomerated with the liquefaction fluid and the native liquids of the well stream, separating the gas from Athe agglomerated liquids und-er high pressure within said retrograde condensation range, and recycling a portion of the separated liquid as the liquefaction fluid.

14. The method of recovering native hydrocarbon products from a well'at pressures within the range of retrograde condensation which includes, flowing a well stream including said native hydrocarbon products from the well at a pressure within the range of retrograde condensation, cooling the well stream, extracting from the well stream heavier hydrocarbon liquids than those which are to beultimately recovered, admixing with the `Nell stream a liquefaction fluid including hydrocarbon lcomponents of substantially the same composition as some of the native hydro-- carbon componentsv to be recovered from the well stream and in such quantities as to induce precipitation and increased recovery of liquefiable fractions of the well stream while maintaining said stream under high pressure, flowing the admixed fluids concurrently while subjected to surcial contact under high pressure, whereby native liquefiable fractions are precipitated and agglomerated with the liquefaction uid and theA carbon products from a well at pressures Within the retrograde condensation\range which includes, flowing a well stream including said native hydrocarbon products from the well at a pressure within the range of retrograde condensation, separating liquids in the -stream from uncondensed gas at a high pressure, carrying off the uncondensed gas, conducting a portion of thel separated liquids from the separation step, conducting another portion of the separated liquids from the separation step, heating the last-named portion ofA the liquids to raise the temperature thereof, and .injecting liquids which have been heated into the flowing stream in advance of the separating step, while maintaining said stream under a high pressure, concurrently flowing the adm ixed fluids while subjected to surficial contact under high pressure, whereby native liqueable fractions are precipitated and agglomerated with the liquefaction iluid and native liquids ofthe well stream.

, 16. The method of recovering native hydrocarbon products from a Well at pressures within the range of retrograde condensation which includes, flowing a well stream including said native hydrocarbon products from the well at a pressure within the range of retrograde condensation,

admixing with the well stream a comparatively heavy liquefaction liquid including hydrocarbon components substantially the same as some of the, native hydrocarbon components recoverable from the well lstream in such quantities as to increased recovery of liquefiable ,fractions from the said gaseous stream while maintaining said stream under high pressure, flowing the admxed iluids while subjected to surcial Contact under high pressure, whereby the native liquefiable fractions are precipitatedand agglomerated with the liquefaction fluid and condensed liquids of said'stream,v and vseparating gas from the said agglomerated liquids under high pressure within said high pressure range.

17. The -method of recoveringnative hydrocarbon products from a well at pressures within the range of retrograde condensation which includes, flowing a well stream including {said native hydrocarbon products from the well ata pressure within the range of retrograde condensation, primarily extracting from the well.

stream heavier hydrocarbon liquids than those which are to be ultimately recovered, cooling the well stream after such primary extraction, admixing with the Well stream. a, liquefactio'n iluid including hydrocarbon components of lsubstantially the same composition as some o f the.

native hydrocarbon components recoverable from the well stream and in such quantities as to nduce precipitation and increased recovery 'of liqueflable fractions of the well stream while' lmaintaining said stream under a high pressure,

owing the admixed uids concurrently while subjected to surcialcontact under high pressure, whereby native liqueable fractions are precipitated and agglomerated with the liquefac; tion fluid and the native liquids of the well stream, and separating the gas from the agglomerated liquids under high pressure within said retrograde condensation range. l

18. 'I'he lmethod of recovering liqueable hydrocarbon constituents from distillate type wells which includes, owing the stream from the well under high pressure within the range of retrograde condensation, cooling the gas stream by admixing therewith a cold liquefaction medium while maintaining high pressure to condense liqueilable hydrocarbon constituents, flowing the admixture concurrently in intimate contact to amplify the condensation of liquefiable hydrocarbon constituents, conducting the admixture in an elongate path to a point of separation and separating the uncondensed gas from the ad- 'mixture at a pressure within the retrograde condensation range, carrying off gas from the point of separation at a pressure within the range of retrograde condensation, carrying olf a portion of the liquids, and recirculating anotherportion of the liquids as the cooling and liquefaction medium;

JAY P. WALKER.

EDWIN V. FORAN. 

